Proposal of generic_steering_controller

[silanus23]

This issue is describing ros-controls/ros2_controllers#1822

Is your feature request related to a problem? Please describe.
This proposal follows up on ros-controls/ros2_controllers#692 of controllers and related maintainer comments. Main idea comes from #692. While the steering/traction joint naming issue raised in #692 has already been addressed in the library, this proposal focuses on extensibility. Currently supports three kinematic types but is difficult to extend to others but the proposed plugin-based approach makes extension to other robots straightforward. A kinematically agnostic controller could provide much wider support. Doing this by making user create a plugin derived from kinematic_model_base .

Describe the solution you'd like
This architecture is a considered evolution of the existing steering_controllers_library , addressing its key limitations. Here are the changes made on top of this file:

Function Name	In Both?	Changed?	Notes
reset_controller_reference_msg	Yes	Minor	Only namespace/class name differs; logic is identical
Constructor	Yes	Changed	Loads kinematic plugin too
on_init	Yes	Minor	Only parameter listener type differs
set_interface_numbers	Yes	Same
on_configure	Yes	Changed	Simpler, less odometry config, more plugin logic; library: more odometry checks
reference_callback	Yes	Same
command_interface_configuration	Yes	Same
state_interface_configuration	Yes	Minor	Adding steering differently and loggin more
on_export_reference_interfaces	Yes	Minor	Only message type/class name differs
on_set_chained_mode	Yes	Same
on_activate	Yes	Minor	Sets all command interfaces to NaN, library only resets
on_deactivate	Yes	Minor	Sets all command interfaces to NaN, library only sets command interfaces
update_reference_from_subscribers	Yes	Same
update_and_write_commands	Yes	Changed	Uses kinematic plugin, library uses odometry; both clear reference after use
initialize_implementation_parameter_listener	No	Only this branch

Describe alternatives you've considered
A direct change or keeping both controller for steerable robots

Additional context
Proof of Concept
Proof of concept repos: generic_steering_controller_demo, four_wheeler_demo. These demonstrate 4x4 and carlike robots using the proposed structure.

Future steps:
First of all six_wheel_rover plugin should be added after that more plugins can be added.
In the next step this can be modified to provide support for URDFParsingKinematics making the controller taking data directly from urdf and no need for parameters. Making this as the maintainer's recommendation fully aligning with "agnostic to the source of info". At the very last stage maybe adding a support for 6dof controller.

If this approach stabilizes and gains adoption, existing controllers in steering_controllers_library could be incrementally migrated to this structure. That way, we avoid duplicated code paths long-term without breaking current users.

Do you agree this direction (plugin-based generic steering controller inside ros2_controllers) is the correct path?

Note: I know I probably need to add steering controllers library writers in sign but didn't want to make it without permission